This invention relates generally to temperature measurement apparatus, and more specifically to relatively high temperature measurements extending to approximately 2400.degree. C.
The accurate measurement of high temperatures has always been and is a major industrial problem. Severe operating environments limit the use of standard temperature measuring techniques; conventional materials and design constraints limit both the maximum operating temperature and their use in chemically aggressive environments. The invention is directed toward a measuring technique which can improve upon existing techniques, such as thermocouples, resistance thermometers and pyrometers, or provide a new measurement capability in regimes where conventional techniques do not operate. The temperature measuring device may find application in a large number of environments, basically wherever it is desirable to take temperature measurements either for monitoring the temperature quantity per se, or for control purposes, such as, for example, in industrial facilities.
The invention utilizes a blackbody cavity formed on the tip of a light transmitting fiber. The blackbody cavity serves as a signal generator which emits blackbody radiation whose amplitude and frequency spectra are indicative of the blackbody cavity temperature. Radiation from the blackbody cavity is transmitted via the light transmitting fiber to an optical receiving device which converts the received radiation into an electrical signal having a signal characteristic indicative of the magnitude of received radiation. The basic technique set forth above has been described in U.S. Pat. No. 3,626,758 incorporated herein by reference.